cell membrane and heart

Question 1

Definition osmosis

Answer 1

The net movement of water molecules through a partially permeable membrane from a region of high water potential to a region of low water potiential .

Question 2

Solute definition

Answer 2

Substances that dissolve in a solvent

Question 3

Solute and water move…

Answer 3

randomly due to kinetic energy

Question 4

equation for water potential

Answer 4

water potential = osmotic (solute) potential + turgor (hydrostatic) pressure
s + p

Question 5

negative wp =

Answer 5

lower water potential

Question 6

lower water potential means..

Answer 6

higher osmotic potential

Question 7

water potential definition

Answer 7

the potential for water molecules to move freely

Question 8

High –>

Answer 8

low

Question 9

osmotic potential definition

Answer 9

Difference in pressure inside a cell compared to the pressure outside the cell

Question 10

Hydrostatic presssure defintion

Answer 10

the pressure of the fluid applied to the cell membrane by solution inside the cell/ container

Question 11

adding solute means

Answer 11

lower water potential
always -ve Wp

Question 12

more concentrated solution means

Answer 12

more -ve WP

Question 13

osmosis moves

Answer 13

down concentration gradient

Question 14

pure water

Answer 14

Wp of 0kpa at standard conditions - 25oc and 100kpa
low Wp

Question 15

adding solute

Answer 15

lowers WP

as lower conc of water per unit vol
therefore Wp = -ve value

Question 16

more solute dissolved

Answer 16

more -ve Wp
affects pressure on membrane

Question 17

Hypotonic

Answer 17

low solute conc
high wp

Question 18

hypertonic

Answer 18

high solute conc
low wp

Question 19

Hypotonic defintion

Answer 19

osmotic conc of solution surrounding cell is lower than of the cell
water in

Question 20

isotonic

Answer 20

Osmotic conc are equal
no net movement
dynamic equilibrium

Question 21

Hypertonic definition

Answer 21

osmotic conc of solution surrounding cell is higher than of the cell
water out

Question 22

water in….

Answer 22

animal - lysed
plant - turgid
hypotonic

Question 23

Water same

Answer 23

animal - normal
plant - flaccid/ incipient plasmolysis

Question 24

water out

Answer 24

animal - shrivelled
plant - plasmolysed

Question 25

Diffusion

Answer 25

simple or facilitated
down conc gtradient

Question 26

simple diffusion

Answer 26

The net movement of molecules or ions form a high conc to low con

• small soluble non polar molecules
• passive - no ATP - don’t require metabolic energy
• Across phospholipid bilayer

Question 27

facilitated diffusion

Answer 27

Passive - relay on inbiuilr motion of motion of molecules

down conc gradient

• charged ions - polar - by carrier proteins or channel proteins -

don’t diffuse easily- hydrophobic fatty acid in phospholipid bilayer

Question 28

Active transport

Answer 28

the net mevoemtn of molecules from low to high coin using App and carrier proteins

• against conc gradient

-ATP used

Question 29

Fluid mosaic model

Answer 29

• individual phospholipid molecules can move relative to one a other - gibes the membrane a flexible constant changing shape
• portions that are embedded in phospholipid bilayer vary In shape and size and pattern - like mosaic

Question 30

At vs diffusion

Answer 30

both use carrier proteins

Question 31

phospholipid bilayer

Answer 31

• gives membrane fluidity
• Allows lipid soluble substances to enter and leave - prevents water soluble from leaving
• hydrophobic region - barrier to water soluble

Question 32

hydrophobic

Answer 32

lipid tail - forms semi permeable bilyer

Question 33

Hydrophilic

Answer 33

head - polar
- phosphate

Question 34

Glycoprotein

Answer 34

cell signalling, cell recognition (for hormones and neurotramiiter) , binding cells together, act as antigen allows cells to recognise one another

carbohydrate attached to a protein

Question 35

Glycolipid

Answer 35

carb attached to lipid phospholipid

• cell signalling and cell recognition
• helps maintain stability of membrane

Question 36

Cholesterol

Answer 36

Regulates membrane fluidity/ stability - less fluid at high temps

regulates lateral movement of phospholipids

very hydrophobic
pulls together fatty acid tails of the phospholipid
adds strength to the membrane

Question 37

Carrier protein

Answer 37

protein with specific shape that complaints shape of substance to be transported across membrane
- AT and FD

Question 38

Protein channel

Answer 38

protein with specific shape that complaints shape of substate (ion) to be transported across membrane - ternary strcutre specific - FD

down conc

• passing of ion through

Question 39

phosphlipids

Answer 39

can move freely in the bilayer

Question 40

Explain how three features of a plasma membrane adapt it for its functions. (6)

Answer 40

phospholipid bilayer (as a barrier);
forms a barrier to water soluble
allows non-polar substances to pass
bilayer is fluid;
can bend to take up different shapes for phagocytosis / form vesicles / self repair;
channel proteins (through the bilayer)/intrinsic protein;
let water soluble/charged substances through / facilitated diffusion;
carrier proteins (through the bilayer);
allow facilitated diffusion / active transport;
surface proteins / extrinsic proteins, glycoproteins / glycolipids;
cell recognition / act as antigens / receptors;
cholesterol;
regulates fluidity / increases stability;